There is no fucking way in hell you finished Halo 4 in 2.5 hours. 5 hours at the least (playing on easy or normal in a group), they have 8 missions and they are each long as with up to four rally points each. I played on heroic and it took me at least 8 hours, but I wasn't timing, and I actually payed attention to what was going on like Bonn-o-Tron.